Add "bin/herald rule ..." to modify Herald rules from the CLI
Depends on D20566. Ref T13298. See PHI1280. Currently, there's no clean way to disable problematic personal rules. This comes up occasionally and sometimes isn't really the best approach to solving a problem, but is a generally reasonable capability to provide.
Allow Herald rules (including personal rules) to be disabled/enabled via bin/herald rule ... --disable/--enable.
Test Plan: Used the CLI to disable and enable a personal rule.
Reviewed By: amckinley
Maniphest Tasks: T13298
Differential Revision: https://secure.phabricator.com/D20567